1. Field of the Invention
The invention generally relates to a touch technology, and more particularly, to a touch projection system and a touch sensitivity adjusting method thereof.
2. Description of Related Art
Interactive projection technology is a technology enabling a user to perform a touch operation on a projected image, and it uses an invisible light curtain (e.g., an infrared light curtain) generated by an invisible light emitter (e.g., a laser emitter or laser diodes) to cover the entire projected image. When a touch object contacts the invisible light curtain and reflects or blocks an invisible light beam of the invisible light curtain, an image frame capturing apparatus can capture an image frame and then determine a position of the touch object in the image frame so as to perform a touch function.
In the current interactive projection technology, when a projector moves relative to the screen in arrangement, a size of a projected image provided by the projector on the screen can vary according to a distance of the projector with respect to the screen. When the projector is relatively farther away from the screen, the size of the projected image provided by the projector is larger, while when the projector is relatively close to the screen, the size of the projected image provided by the projector is relatively smaller. In the other hand, based on requirements of safety regulations, the power of the invisible light emitter is generally designed as a fixed value, and thus, when the projector is relatively farther away from the screen to cause the projected image to be larger, a requirement for the touch sensitivity must be higher. However, conventional technology is unable to accurately obtain the size of the projected image, and thus is unable to effectively provide suitable touch sensitivity. Even through the image frame capturing apparatus is generally fixedly disposed on the projector, since a range capable for the image frame capturing apparatus to capture an image frame is also influenced by a distance between the image frame capturing apparatus and the screen, it is also unable to accurately know the size of the projected image simply through the image frame capturing apparatus.
The information disclosed in the “Description of Related Art” section is only for enhancement of understanding of the background of the described technology, and therefore it may contain information that does not form the prior art already known to a person of ordinary skill in the art. Further, the information disclosed in the “Description of Related Art” section does not mean that one or more problems to be resolved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art.